It is known in the prior art to adapt the air mass flow that is taken in by the compressor of gas turbines in part load operation by a variable adjustment of the compressor inlet guide vanes. In this way, an efficiency that is as great as possible can be achieved for a given maximum temperature of the exhaust gas. One of the limiting factors for the permissible final angle of the variable compressor inlet guide vanes is in this case a cooling of the intake air in the region of the row of inlet guide vanes and/or the first row of compressor rotor blades and the associated risk of icing. In dependence on the humidity of the intake air, the acceleration of the flow downstream of the row of inlet guide vanes, which leads to the cooling of the flow, may cause icing in the compressor, and consequently an impairment of the integrity of the machine and possibly damage to the machine.
It is customary in the prior art to set definitively fixed values in advance for assumed values of the process parameters. As a result, the operating range of the gas turbine is not fully exploited in every situation.
A variable setting is proposed by JP 2011032869 A, which teaches performing the setting on the basis of the current compressor inlet temperature and the atmospheric humidity. However, the setting on this basis requires the computational determination of a dedicated characteristic map, which among other things represents an undesirably great technical expenditure and possibly requires additional operational measurement stations.